The invention concerns an electromagnetic earpiece with a housing, in which a coil through which an energizing current flows as well as a membrane, are arranged such that the membrane can be excited to vibrate as a result of the energizing current, whereby within the housing internal connection conductors are directed from the coil ends to electrical connections on the housing.
In electro-acoustic apparatuses, and particularly in hearing aid devices, electromagnetic earpieces are used to transduce electrical signals into acoustic signals. Due to the required miniaturization of these apparatuses, hearing aid devices have a problem in that electromagnetic leakage fields emanating from the earpiece interfere with other components of the hearing aid devices. In particular, the reception via an induction, telephone, or hearing coil in a hearing aid device can be disturbed by the leakage field generated by an earpiece.
From the prior art, measures are known in order to confine the leakage field emanating from an earpiece. For example, an induction coil is, in principle, arranged in the housing of a hearing device with an optimally large distance from the earpiece. Furthermore, it is known to provide particular shielding plates. These known shielding plates can, however, only influence a portion of the leakage fields. An optimally complete shielding of the earpiece is therewith not possible.
A cone speaker with a voice coil through which an audio-frequency alternating current i flows is known from Jecklin, Jürg, “Lautsprecherbuch”, Telekosmosverlag, Franckh'sche Verlagshandlung, Stuttgart, 1967, page 37. The cone speaker comprises a membrane that is arranged such that the membrane can be excited to vibrate. Furthermore, the cone speaker comprises wires that supply the alternating current i to the voice coil. Within the cage, internal connection lines are routed from the coil ends of the voice coil to electrical connections on the cage.
German patent document DE 198 54 201 C2 discloses a hearing aid device with an earpiece for sound emission and with an induction coil for inductive acquisition of signals as well as with a compensation inductor for generating a compensation field, whereby the compensation inductor is positioned in the signal line of the earpiece between the induction coil and the earpiece such that its compensation field is directed counter to the magnetic field of the earpiece given operation of the induction coil, and a coupling between the earpiece and the induction coil is prevented.